#include<stdio.h>
int f(int b[][4])
{
    int i,j,s=0
    for(j=0;j<4;j++)
    {
        i=j;
        if(i<2) i=3-j;
        s+=b[i][j];
    } 
    return s;
}
int main()
{
    int a[4][4]={{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};
    printf("%d\n",f(a));
    return 0;
}